Summer Annuals

Description

Sorghum-sudan crosses are a warm-season, or C4, grass. Because warm-season grasses process sunlight into sugars (photosynthesis) differently than do cool-season (C3)grasses, sorghum-sudan:

• must be planted after soil temperatures reach 60°F and are rising.
• grow very little at temperatures lower than 60°F.
• grow best at 77°F and higher.
• will produce a ton of silage with half the rain or irrigation needed by corn silage.

After germination, sorghum-sudans thrive in hot, dry weather. They die soon after a freeze.

These forages produce quick tons of highly digestible (high-energy) silage or pasture; they are an excellent source of pasture for the hottest months.

BMR (brown mid-rib) is a natural trait (not GMO) that produces lower levels of lignin in these plants. This trait transforms sorghum products into highly digestible feed that fuels livestock performance. All the sorghum-sudans in the Byron Seeds lineup are BMR.

Brachytic dwarf sorghum-sudans (a natural trait) provide some good benefits:

• Shorter residual cutting height
• Shorter space between leaves for better leaf-to-stem ratio
• Shorter stalk but with more leaves, a quality improvement
• Higher tillering capacity

Establishment

Sorghum-sudan usually emerges in about 10 days and then can grow 3-6 inches per day. A conventional or no-till drill is used for the seeding, and planting depth should be 1.0-1.5 inches.

Planting after a small grain crop (rye or triticale, for example)requires dealing with the allelopathic effects from the dying grain plants. This can be accomplished with either minimum tillage or heavy application of liquid manure.

Because no herbicides are available for sorghum-sudan, weed-management activities must precede planting.

Management

Sorghum-sudan will be harvested for baleage or haylage about 45 days after planting. Grazing is usually initiated a week to 10 days earlier. Sorghum-sudan is mowed when it reaches a height of 38-40 inches.

Residue heights are also important. Brachytic dwarfs can be mowed with a 4-inch residue, one reason for their popularity. Non-brachytic versions must be mowed with at least 6 inches of residue (above the second growth node) to promote rapid regrowth. Caution: Regrowth can be almost zero if the residual is too short.

Fertilizer needs are 1.0-1.25 units of nitrogen per growing day, i.e., 45-50 units for the first cut and 30-35 units for each subsequent cut. Potassium, phosphorous and sulfur are also needed on most farms. All fertilizer needs are the equivalent of the needs for 100-bushel corn.

Manure can be used for the original application of fertilizer; however, commercial nitrogen is the best source after a cutting. Nitrogen needs for grazed sorghum-sudan must be reduced proportionally so that cows can be brought in to graze earlier without danger of nitrate poisoning. Sorghum-sudan should not be grazed for 7-10 days after a killing frost as it takes about seven days for the prussic acid produced by the frost to dissipate.